Process of making window-envelops.



W. E. SWIFT.

PROCESS 0F MAKING WINDOW ENVELOPS.

APPLICATION FILED MAR. 2. |915.

Patented. Apr. 30, 1918.

IMI

Mayan #my Mmea 'WILJLRJD E. SWIF'LOF WORCESTER, MASSACHUSETTS, ASSIGNOR T0 UNITED STTJE ENVELOPJE COMPANY, 0F SPRINGFIELD, MASSACHUSETTS,- A

MAINE.

CORPORATION 0F PROCESS 0F MAKXNG WINDOW-ENVELOPS. i

Specification of Letters Patent.

Patented Apr. 30d, lidi@ Application filed March 2, 1915. Serial No. 11,574.

To all whom it may concern.'

Be it known that l, WILLARD E. Swrrn a citizen of the United States, residing at Worcester, in the county of Worcester and Commonwealth of Massachusetts, have 1nvented a new and useful Improvement 1n Processes ofMaking Window-Envelope, of which the following, together with the accompanying drawings, is a spec1ficat1on.

The present invention relates to a method of makin window envelops, and has particular reference to the type of window en velops which are characterized by a substantially transparent patch secured within the inside of the envelop and covering an opening formed in the front side of the same. The .materiall commonly used for such patches is commercially known as glacine paper; the same possesses a considerable degfree of transparency, which lends itself peculiarly to the manufacture of such envelops. The resent invention is concerned with the prodhctinn of an envelop of this type in which the window, or transparent y patch, is made to possess a greater degree of transparency than is possessed b the windows of such envelops now in or inary use; the features of said invention are set forth in the following description and pointed out in the annexed claims, reference being had to the accompanying drawings, in which- Figure 1 represents a viewofthe rear or inner side of an envelop blank, sultable for the application of my invention thereto.

Fig. 2 re resents a front view of a com'- pleted enve op embodying my inventlon and made in accordance with the method which forms Aa part of the same.

Similar reference characters refer to similarparts in both figures.

T ie shape of the envelop to which my invention is a plied is immaterial; the envelop shown 1n the drawings, which is illustrative merely, ismade from a blank havyin a body portion l, forming the front si e of the com leted envelop, side or end flaps 2 and 3 W ich are folded inwardlyto form the back side of the envelop, a bottom iap 4, and a closure flap 5. The body portion l has a suitabl dis osed elon ated openin 6 therein, w ich 1s covered y a patch of transparent or glacine paper said atch being somewhat larger than sai opening and overlapping the edges ont the 4like surface ofordinary paper.

same in all directions, being secured to the gummed or top side of the blank by adhesive material, indicated at 8, which surrounds said opening, so that the blank when folded in the ordinary manner, provides an envelop having a transparent covering for the opening in its front side, which covering or patch is attached upon the inside of the envelo The g acine paper ordinarily used as the material for such patches differs widely in composition and texture from Ordinar;1 opaque or semi-opaque paper; the glacine paper is close-knit, by reason of the preponderance of cellulose matter in the composition thereof, and moreover, said paper presents a smooth, hard and relatively 1mpenetrable surface, quite unlike the nap- The cellulose character of the material gives it its transparent quality; however, I have discovered that the degree of such transparency may be very considerably increased by the treatment of one or both surfaces with a liquid, such asa varnish, or other substantially transparent liquid having resinous or other transparent matter in solution. p

I am aware that window envelops have been made heretofore by applying oleaginous substances, in liquid form, to a space upon the front or address side of the envelops to render the same transparent, and li make no claim to this method of manufacture, nor to the article produced thereby. lin all such prior processes, the production of Aa transparent panel depends upon the passage of the liquid through the paper from one surface'to the other; the adaptability of most commercial grades of paper, from which envelops are made, to this treatment, by reason of the loosely-knit7 coarse-iibered composition of the material and the villous, nap-like character of the surface thereof, is well recognized. The action is essentially one of permeation, and as, a consequence the greater portion of the liquid 1s completely removed and isolated from the drying action of the atmosphere, the evaporation of the liquid is practically never completed, and the window or panel, while possessing a certain limited degree of transparency, invariably is of an oily sticky nature on both sides and is never thoroughly drya In carrying out my invention, the transparent glacine patch 7 is applied to the opening- 6 in the envelop blank in the usual manner; in some cases the reverse surface of the patch, z'. e., the surface Which is not brought into contact with the adhesive 8 surrounding the opening, may already have received a coating of the transparent liquid above referred t0, either before or after being cut into patch form. Or, obviously, the coating of transparent liquid may be applied to this surface of the patch after the latter has been secured over the opening in the blank, by any suitable means, such as a brush, or a die, or a roller coated With the liquid. Preferably, a solution having the property of drying quickly is used;,but I do not Wish to confine myself to the use of such a solution, since it is manifest that the character of the paper itself, by reason of its impenetrability, is conducive to the rapid drying of the liquid, since said liquid lays on the surface of the paper in a thin lm, completely eX osed to the evaporative action of the air. onsequently there is no impairment ofthe adhesive qualities of the other. surface of the patch since there is absolutely no ermeation of the liquid to said other sur ace to render the same oily,- and thereby unsuitable for contact with the glue 8.

irrespective of Whether or not this treatment of the reverse surface of the patch is afforded, the blank, with the patch applied thereto is now in condition for folding, and

in condition for the treatment of that surface of the atch lying on the address or front side of) the envelop, either before or afterthe folding of the blank to form a completed envelop,.li`ig. 2. This latter step involves the subjection of the successively fed blanks, or envelops, as the case may be, to the action of a'suitable coating device 'or die, corresponding in shape to, but

slightly smaller than the opening 6 in the address side of the envelop; said die prints or lays a film of the varnish or other transparent liquid upon the outer surface of the patch, preferably' just within the edges of said opening 6, as indicated by the broken line 9, Fig. 2. The advantages accruing from the treatment of the patch in this manner have already been set forth; the transparency of the patch is materially increased, the liquid dries rapidly, owing to its complete exposure to the air, and there is no permeation of said liquid to the reverse side of the patch, necessitating a drying of this side before the blank is folded, or, if already folded, necessitating a delay in stacking the completed envelops to alloW the patches of the same to dry. On the contrary, the envelops are ready for instant use as soon as the short time required for the evaporation of the thin film of liquid on the front sides thereof has elapsed.

I claim,

1. The herein described method of making a tivo-piece Window envelop, comprising the attachment of a transparent patch to the inside of an envelop blank to cover an opening in the body of the blank, the coating of the inside surface of said patch With a transparent liquid before said blank is folded, and the folding of said blank to form a completed envelop.

2. The herein described method of making a tWo-piece Window envelop, comprising the attachment of a transparent patch to the inside of an envelop blank to cover an opening therein, and the printing of a film of transparent substance in liquid form upon the outside surface of said patch, Within the edges of said opening on the front side of said blank.

3. The herein described method of. makinga Window envelop having a transparent patch covering the opening in its front side, comprising, coating of the insidesurface of said patch with a transparent liquid before the blank is folded, folding said blank to form a completed envelop, and printing a film of transparent substance in liquid form upon the outside surface of the patch, Within the edges of the opening in the front side of the envelop.

Dated this 25th day of February, 1915.

WILLARD E. SWFT.

Witnesses Narnia WHALEN,

PENELQPE COMBERBAGH. 

